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Diseases are diagnosed by analysis carried out by biomedical scientists in pathology. Several techniques and procedure are used to analyse samples in order to make diagnoses. There are four different pathology departments. They are haematology, microbiology, clinical chemistry, and cellular pathology. All pathology disciplines make diagnoses and monitor diseases by using different techniques, methods and procedures. In this essay the techniques, procedures and methods of tests biomedical scientist use in diagnosing and monitoring of diseases in all the four pathology is explored. In addition, any further investigation that can be carried out as a consequence of initial results obtained from such test is also explored.
Full blood count (FBC) is a clinical procedure practised in the haematology department which tests for abnormalities in the blood. It is a test used in diagnoses of diseases such as anaemia which are characterised by the significant decrease in the red cells and haemoglobin. An FBC is used to obtain counts of the level of different cells within the body system. The number of the cells, the size and proportions of these cells and the haemoglobin level is measured in an FBC. (Carter et al., 2005) . Full blood count is measured on a whole blood sample by using an automated machine referred to as FBC analyser. The analyser measures the platelet, red cells and the white cells. The results are sent to a computer which shows any abnormalities. The results also include the mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and the red cell distribution width (RDW). (Dugdale 2006) RWD is a measure of the variation of red cell in the blood sample. Diseases that can be diagnosed using FBC analysis are
Glucose is a simple sugar that serves as an energy source for cells in the body. The blood glucose concentration is controlled by hormones such as insulin in the body. The normal range of blood glucose concentration is between 3.6 and 5.8mM. However, the blood glucose level fluctuates throughout the day. A radical increase or decrease in the mean blood glucose level indicates a medical condition. In addition, a significant increase and decrease in the blood glucose concentration is referred to as hyperglycaemia and hypoglycaemia respectively. Glucose testâ€™s are one of the major tests performed in the clinical biochemistry department. It is used to make diagnoses of diseases such as diabetes which are characterised by hyperglycaemia. For accurate glucose analysis, the suitable sample used in measuring of the glucose concentration is the blood sample which is collected in a tube containing are fasting glucose testing. Fluoride oxalate inhibits enzymes involved in glycolysis which aid the prevention of the red cells from metabolising the glucose in the sample. Fasting blood glucose are measured to make initial diagnose of diabetes but it may not show the accurate parameter. For fasting glucose testing, patients are required to fast for 8 hours before taking the blood test. Diabetes condition require long term maintenance of the Mean Blood Glucose (MBG). Haemoglobin A1c (HbA1c) is formed when glucose binds to a particular site in the haemoglobin which indicates that the higher the glucose in the blood, the higher HbA1c. HbA1c is measured in a blood sample to investigated the mean blood glucose (MBG) of a diabetes patients accurately. The difference between fasting glucose test and HbA1c test is that fasting glucose measures the blood glucose level at that present time whereas, HbA1c is used to estimate the mean blood glucose over the last 60 days. In addition, further Investigation can be carried out to confirm diabetes diagnoses. Micro albumin is measured in urine samples and its presence in the urine is indicates some form of a kidney damage which is caused by diabetes.
Swab test are one of the diagnostic tests performed in the microbiology department. They are requested by doctors to isolate and identify the pathogen in a specific site of an infection. A swab is a short rod with a small wad of cotton around it. A sample is taken by brushing the swab on the infected site which is transported to the laboratory by an appropriate medium. After inoculation, swabs are processed and microbes are cultured. After, antibiotic sensitivity test is performed on the isolated microbes to enhance treatment. Swabs can be taken from the throat, mouth, wounds, ear, and eyes and vagina. Different pathogen colonises specific site in the skin and tissues. In addition, Bacteria species that colonises the throat or nose includes streptococcus viridians, diptheroids and streptococcus pyogenes which are isolated from about 30% of patients with acute sore throat. (Shanson 1989).
Biopsy is the test performed in the histology department to diagnose diseases or show the extent of the disease. For example, cancerous tissues can be tested for malignancy. The test involves the removal of tissues from patients during surgery for examination under the microscope. When specimens get to the laboratory, it is firstly fixed unless immediate diagnosis is necessary. Fixation is used to maintain the morphology of the specimens. Complete fixation helps to protect bone and surrounding soft tissue from damaging effects of acid decalcification (Callis 2008). When a specimen arrives in the laboratory, it is firstly dissected by the pathologist before it is fixed. Fixation of tissues can be done by either physical or chemical methods. However, the type of fixation adopted in histology is the chemical method. Physical fixation includes freeze drying , microwaving and heat fixation while chemical fixation method include coagulant fixatives, dehydrant coagulant fixatives and non coagulant cross linking fixation.(Callis 2008).The common chemical fixative used in histology is formaldehyde which is an example of a non coagulant fixation. After fixation, the tissues are then processed through stages. Tissue dehydration is the first stage of processing, during this stage, removal of water and fixative from tissues components are done. Examples of dehydrating reagents include ethanol, methanol and acetone. Furthermore, dehydration process are carried out through increasing concentration of reagents as excessive dehydration which can cause hardening and shrinking of the tissues. If the dehydrant of choice is ethanol, the tissue is first immersed in 70% ethanol in water, followed by 95% and 100% solution (Callis 2008).The next stage is the replacement of dehydration solution with clearing reagents to prepare tissues for further processing.. Examples of a suitable clearing reagent are toluene, xylene and chloroform. Finally, infiltration and embedding of tissues in paraffin wax is carried out. Embedding involve dispensing of paraffin wax into a mould, proper orientation of the specimen into the mould, and attachment of cassette into the mould to produce a flattened block. The mould is placed in a cold plate immediately after this process to solidify. The tissue is hardened by saturating it with wax to prevent alteration of the structure of the tissue during microtomy. Microtomy is the method where by moulded tissues are trimmed and sectioned by using a microtome to give ribbons of tissues which is placed in a floatation bath. After, the sections are attached to a slide which are later stained by using either an automated machine or manually. There are various staining technique that are adopted in histology but the Haemolysins and Eosin is mostly used. Finally, after slides are stained, they are then inspected in the microscope by the pathologist.
In conclusion, biomedical scientists work in relation with the doctors to give proper diagnoses of diseases and treatment. This essay has explained in depth the diagnostic approach pathology takes is very important and essential in the treatment of patients in order to demonstrate not only the processes of the treatments but also the order by which they are carried out.